Mr. Kristof draws an association between the occurrence of community-acquired MRSA in a farm town in northwestern Indiana to the death of a family doctor. From the facts presented, there is no evidence that the doctor died of MRSA. Without a proper investigation, such anecdotal information may deter doctors from caring for MRSA patients. Recall the early stages of the H.I.V. epidemic.

Second, Mr. Kristof links MRSA in the Indiana community to that of possible transmission from local hog farms. As has been well publicized, communities across America are experiencing outbreaks of MRSA infections, including our communities in Memphis and Nashville. We have no reason to think that this town in Indiana is different from other locales in the United States where a majority of skin infections presenting to the emergency room are caused by MRSA.

Also, MRSA infection transmission is bidirectional — how do we know that the hogs may not be getting the infections from humans?

Lastly, Mr. Kristof states that officials were not called because it would outrage the neighbors. When there is smoke, one calls the fire department, not the local paper.

But we do agree with Mr. Kristof that there is no evidence that pork meat causes MRSA infections, and we further agree that the “insane overuse” of antibiotics is playing a role in the MRSA epidemic — but it is not just in our livestock feeds, it is also in our primary and specialty doctors’ clinics.

Manoj Jain
William Schaffner
Memphis, March 14, 2009

The writers, both medical doctors, are, respectively, an infectious-diseases specialist and adjunct assistant professor at the Rollins School of Public Health at Emory University; and professor and chairman of the department of preventive medicine, Vanderbilt University School of Medicine.

To the Editor:

Nicholas D. Kristof’s March 12 column suggesting that incidences of MRSA in Indiana were caused by hog farms is sensationalistic.

We are responsible for the safety of our workers and our communities — we live and work here, too. The illnesses in Camden are unfortunate, but do not originate with the area’s hog farms.

Our industry has financed a number of MRSA research projects, with no conclusive evidence linking a hog-to-human transmission of the bacterium. And according to the Centers for Disease Control and Prevention, having contact with pigs does not increase one’s chance of getting MRSA.

As an infectious-diseases physician, I read with interest Nicholas D. Kristof’s column about MRSA in pigs and people in Indiana.

A crude relationship exists between the increasing use of antibiotics and the selection of resistant strains. In the United States methicillin resistance appeared in the 1970s in several hospitals and has continued to challenge infection-control experts. But it was the pen of people, not the pen for pigs, that was the primary selecting force.

Once MRSA appeared, the expansion of its prevalence was caused not so much by antibiotic use but by person-to-person transmission. Infection control is the key to limiting MRSA, although I do agree that we can abandon the routine use of antibiotics in animal husbandry.

From the perspective of the Staphylococcus aureus (including MRSA), the organism is an equal opportunity guest in the nasal passages of man or mammal.

Richard P. Wenzel
Richmond, Va., March 12, 2009

The writer is a professor and chairman of the department of internal medicine at Virginia Commonwealth University.

To the Editor:

Like Nicholas D. Kristof, I’m not opposed to hog farmers or people consuming meat. But we are paying the price for having as much meat as we want, whenever we want, and cheaply, too. Millions of animals cannot be forced to grow on schedule without subjecting them to conditions that require the use (and abuse) of antibiotics.

Technology can control nature only for so long. If we insist on a daily practice of having our steak and eating it, too, then we must expect a nice big helping of superbugs on the side.

Lisa Eicher
East Northport, N.Y., March 12, 2009

To the Editor:

The sharing of methicillin-resistant Staphylococcus aureus (MRSA) between pigs and people illustrates that many microbes infect across species, and that animal, human and environmental health are inextricably linked.

Unfortunately, during much of the 20th century, communication and collaboration among physicians, veterinarians and other health-science professionals waned. Institutional, geographic and financing barriers often prohibit meaningful interactions among experts. The result is that surveillance, research, prevention and control measures for cross-species infections like MRSA are not coordinated and optimized.

“One Health” is a concept that promotes the integration of human, animal and environmental health. If we are to face the challenges of the 21st century, we will need a new paradigm in how we approach disease. Carrying out One Health in government, academia and industry would be an important step in this direction.

The writers are, respectively, a medical doctor, a veterinarian, a medical doctor and a research scientist who advocate, promote and support the One Health concept through their Web site and other endeavors.

Correction: March 21, 2009
A letter from the Indiana Pork Producers Association on Thursday about MRSA, or methicillin-resistant Staphylococcus aureus, referred to it incorrectly. It is a bacterium, not a virus.